The present invention relates to an electrical apparatus adapted to allocate power between two or more power loads. As such, the present invention is particularly useful with loads requiring relatively high currents, and may be used in conjunction with current limit controls as an electrical energy conservation technique. In addition, the present invention may be used to control the cycles of a single appliance, such as an air conditioner, gas furnace or heat pump so as to enable those devices to operate on a more efficient basis.
Various timing devices have been used in the past to control different electrical functions. These timing devices have included both mechanical timers and electrical timing devices, including capacitive systems and digital timing systems. One example of an electronic timing device is shown in U.S. Pat. No. 2,676,052 issued Apr. 27, 1954 to Rockafellow which is adapted for controlling a welding machine. In this device, power is provided to a plurality of loads, one after another, after which the power control operation is concluded. In U.S. Pat. No. 3,470,458, issued Sept. 30, 1969 to Corey, a solid-state load control is shown that includes an adjustable time delay so that once an apparatus is turned on, there is a delay before the circuit is actually activated. The amount of time delay is determined by an adjustable RC circuit connected to a transistor.
In addition to these types of control circuits, other timing devices have been developed in the past. However, none of the devices have utilized self-toggling circuits so that a continuous, repetitive cycling may be accomplished. Further, no prior art is known by the applicant which utilizes a condition responsive device as part of the timing circuit so that the timed durations may automatically vary in response to external conditions, such as temperature. Accordingly, there is a need for an improved timing device that can regulate power in a repetitive manner among two or more loads, and a need exists for a control device that varies the duration of power supplied to different loads in a manner that responds to the environment.